Wellbores are drilled to, for example, locate and produce hydrocarbons. During a drilling operation, it may be desirable to perform evaluations of the formations penetrated by the wellbore. In some cases, a drilling tool is removed and a wireline tool deployed into the wellbore to test and/or sample the formation and/or fluids associated with the formation. In other cases, the drilling tool may be provided with devices to test and/or sample the surrounding formation and/or formation fluids without the need to remove the drilling tool from the wellbore. These samples or tests may be used, for example, to characterize hydrocarbons.
Formation evaluation often requires that fluid(s) from the formation be drawn into the downhole tool for testing, evaluation and/or sampling. Various devices, such as probes, are extended from the downhole tool to establish fluid communication with the formation surrounding the wellbore and to draw fluid(s) into the downhole tool. Fluid(s) passing through the downhole tool may be tested and/or analyzed to determine various downhole parameters and/or properties. Various properties of hydrocarbon reservoir fluids, such as viscosity, density and phase behavior of the fluid at reservoir conditions, may be used to evaluate potential reserves, determine flow in porous media and design completion, separation, treating, and metering systems, among others.
Additionally, samples of the fluid(s) may be collected in the downhole tool and retrieved at the surface. The downhole tool stores the formation fluid(s) in one or more sample chambers or bottles, and retrieves the bottles to the surface while, for example, keeping the formation fluid pressurized. These fluids may then be sent to an appropriate laboratory for further analysis, for example. Typical fluid analysis or characterization may include, for example, composition analysis, fluid properties and phase behavior. Additionally or alternatively, such analysis may be made at the wellsite using a transportable lab system.